Growth and Development of Soybean Root Systems

Abstract

This chapter presents a generalized description of soybean root systems and discusses briefly the influence of plant genotype and carbohydrate supply on root growth and development. Development of a soybean root system begins when the radicle emerges from the seed. Taproots can reach depths of more than 1.5 min the field, but often their growth terminates much sooner because of unfavorable soil conditions or damage to the apex. A large portion of the root system consists of four to seven extensively branched, second-order roots ongmating from the basal portion of the taproot. Development of the root system in the field is strongly linked to shoot development. Reduced root growth during seed development implies that carbohydrate supply might limit root growth during that stage. Growth and development of soybean root systems also are strongly influenced by genotype. Differential growth rates can result in differences in volume of soil penetrated by root systems, total surface area of root system, and root density.